Hopefully, when we get to know Thalia's mom, we'll get some insight on how she treats her daughter at home. Maybe Thalia has certain other rules she has to follow we don't know about yet. I bet her mom, and poor poor Pat of course, have some problems keeping the little hormone driven teenager from doing stupid things like touching herself when it's not appropriate or leaving wet stains all over the place after sitting down. There have to be rules to control such behavior or at least direct it in a constructive direction for Thalia to grow up a better woman one day. And there must be some kind of incentives for following the rules or even punishments if she doesn't.
Damn, somehow my mind is already running wild with the possibilities...